METRON QA-ES, User & Service Manual, Page: 41 / 55

Appendix A - GLOSSARY OF TERMS USED
Bipolar Electrosurgery Electrosurgery where current flows between two bipolar electrodes that are posi-
tioned around tissue to create a surgical effect. Current passes from one elec-
trode, through the desired tissue, to the other electrode, thus completing the cir-
cuit without entering any other part of the patient's body. Neutral plates are not
employed in the bipolar technique. Both electrodes are generally of the same
size.
Bipolar Output An isolated electrosurgical output where current flows between two bipolar elec-
trodes that are positioned around tissue to create a surgical effect in that tissue
(usually desiccation).
Blend A waveform that combines features of cut and coag waveforms; current that cuts
with varying degrees of hemostasis.
Crest Factor The amount of heat generated is relative to the mean power value. The crest
factor depends on the load resistance and is defined as the ratio of peak value to
effective value. A sine wave has a crest factor of 1.4 and provides the cleanest
form of cutting.
Diathermy, also Surgical
Diathermy; Electrosurgery A surgical technique used to cut or coagulate cellular tissue. To avoid muscle
contractions, only high frequency currents and voltages of more than 100 kHz
are used. The electric current directs the heat into the tissue. The patient is con-
nected to two electrodes, allowing the current to flow through the body. The ac-
tive electrode will generate a large amount of heat, due to the high current densi-
ty and the small surface of the electrode.
ESU Electrosurgical Unit. This is a term which is inclusive of both the electrosurgical
generator and its connecting cables.
Cut (Cut Mode, Pure Cut) A low voltage, continuous waveform optimized for electrosurgical cutting.
Isolated Output The output of an electrosurgical generator that is not referenced to earth ground.
Monopolar Electrosurgery A type of electrosurgery involving a small (active) electrode and a large neutral
(neutral plate) electrode. The small surface of the active electrode provides very
good results in coagulating and cutting.
The neutral plate of modern units is
split, thus controlling the circuit, including the contact between electrodes and
patient.
Monopolar Output A grounded or isolated output on an electrosurgical generator that directs current
through the patient to a patient return electrode.
Resistance (Impedance) Resistance to the flow of alternating current, including simple direct current re-
sistance and the resistance produced by capacitance or inductance. The resis-
tance of a material is its tendency, measured in ohms, to oppose the flow of
electric current or, viewed another way, the material's tendency not to conduct
the current.
REM Return Electrode Monitor.
A-1